1. Field of the Invention
The present invention relates to a ski boot made of man-made material, the lower part of which consists of a shell surrounding the foot and the heel and the upper part of which consists, in a known fashion, of a cuff with a hinge on the shell, open at the front and surrounding the lower part of the leg.
2. Description of the Prior Art
It is the foot in a ski boot, in particular its inside edge, which controls the movement of the skis via the shell. It is therefore very important for the shell to mould to the shape of the foot, especially its inside edge, as far as possible, as this determines the precision of the movement of the skis.
Given the morphological differences of the foot conditioned by individual factors (height of the person, shoe size, gender etc.) or ethnic ones (differences between the feet of Japanese, Americans and Europeans), it is essential for the shell to have a system of adjustment for its inside volume in order to adapt to these anatomical differences.
Prior Art efforts to solve these problems have led to the creation of several types of boots.
The first type is so-called flap boots commonly called "overlapped boots" or "front entry boots". These boots use a semi-rigid shell with a slot on the top, forming two overlapping tongues or flaps allowing the foot to be inserted. By definition and in the remainder of the text, the term inside flap shall refer to the flap corresponding to the inner or inside edge of the foot and outside flap shall refer to the flap corresponding to the outer or outside edge of the foot. In these boots, when the boot is fastened with the aid of a buckle or other means, the inside flap of the shell covers the outside flap. In a known fashion, the shell with flaps is joined to a cuff with a hinge which also has overlapping flaps. In the boots illustrated for example in FR-A-1 511 824 or DE-A-2 024 046, the flaps of the shell and the flaps of the cuff overlap and are placed all on the same side, i.e. the inside flap over the outside flap so that the inside flap is on top and towards the outside.
The advantage of this system is the ability of the shell to be deformed due to the effect of the buckles allowing it to adapt to the shape and size of the foot, while ensuring that fastening pressure is evenly distributed over the foot. However, in this design, the inside flap of the shell when it covers the outside flap gradually loses contact with the inside edge of the foot as it comes closer to the top. Furthermore, in this case, the end of the lever of the buckle is positioned on the outside edge of the foot, near the sole, which could cause the skier to fall when it comes into contact with the snow when the skier puts his weight on the edge of the ski.
DE-A-1915 442 discloses a ski boot consisting of a rigid plastic shell to which a leather upper is added. In this supple unhinged upper, each flap on the top of the foot is connected by a supple membrane to the corresponding flap on the lower part of the leg. If, in an illustrated embodiment, the outside flap can cover the inside flap on the top of the foot, this necessarily means that the corresponding flaps on the lower part of the leg also overlap in the same direction. This positioning has the disadvantage of requiring buckles to be placed on the inside edge of the boot, which would be a hindrance when skiing to say the least. This certainly explains why boots of this type have never been marketed.
The second type is boots with a tongue. These make use of a shell which is wide open on the top of the foot to make fitting easy. This opening is covered by a forward-hinged tongue, ensuring both that the boot is watertight and that the side joints come closer due to the effect of the buckles by virtue of the wedge effect. Such a process is described in particular in FR-A-2 371 896 of the Applicant. This technique has the advantage for the user of making the boot easy to put on and take off by pivoting the tongue. However, as the side joints are short, the foot is not sufficiently covered, which is detrimental to the quality of the contact between the inside edge of the shell and the inside edge of the foot. Furthermore, the fastening devices are positioned fairly low in these boots.
A third type of boots called "rear entry boots" has recently come onto the market. These have the particularity of possessing a rigid and indeformable shell shaped like a clog. The boot is fastened by means of a wire-operated upper tile-shaped part. This means that the foot is kept away from the shell. This type of boot is not very technical and does not resolve the problems posed.